Measurement of the <i>t(t)over-bart(t)over-bar</i> production cross section in <i>pp</i> collisions at √<i>s</i>=13 TeV with the ATLAS detector



Aad, G, Abbott, B, Abbott, DC, Abud, A Abed, Abeling, K, Abhayasinghe, DK, Abidi, SH, Abramowicz, H, Abreu, H, Abulaiti, Y
et al (show 2859 more authors) (2021) Measurement of the <i>t(t)over-bart(t)over-bar</i> production cross section in <i>pp</i> collisions at √<i>s</i>=13 TeV with the ATLAS detector. JOURNAL OF HIGH ENERGY PHYSICS, 2021 (11). 118-.

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Abstract

<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>A measurement of four-top-quark production using proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the Large Hadron Collider corresponding to an integrated luminosity of 139 fb<jats:sup><jats:italic>−</jats:italic>1</jats:sup> is presented. Events are selected if they contain a single lepton (electron or muon) or an opposite-sign lepton pair, in association with multiple jets. The events are categorised according to the number of jets and how likely these are to contain <jats:italic>b</jats:italic>-hadrons. A multivariate technique is then used to discriminate between signal and background events. The measured four-top-quark production cross section is found to be <jats:inline-formula><jats:alternatives><jats:tex-math>$$ {26}_{-15}^{+17} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mn>26</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>15</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>17</mml:mn> </mml:mrow> </mml:msubsup> </mml:math></jats:alternatives></jats:inline-formula> fb, with a corresponding observed (expected) significance of 1.9 (1.0) standard deviations over the background-only hypothesis. The result is combined with the previous measurement performed by the ATLAS Collaboration in the multilepton final state. The combined four-top-quark production cross section is measured to be <jats:inline-formula><jats:alternatives><jats:tex-math>$$ {24}_{-6}^{+7} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mn>24</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>6</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>7</mml:mn> </mml:mrow> </mml:msubsup> </mml:math></jats:alternatives></jats:inline-formula> fb, with a corresponding observed (expected) signal significance of 4.7 (2.6) standard deviations over the background-only predictions. It is consistent within 2.0 standard deviations with the Standard Model expectation of 12<jats:italic>.</jats:italic>0 ± 2<jats:italic>.</jats:italic>4 fb.</jats:p>

Item Type: Article
Uncontrolled Keywords: Hadron-Hadron scattering (experiments), Top physics
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 12 Jan 2022 16:17
Last Modified: 18 Mar 2024 04:04
DOI: 10.1007/JHEP11(2021)118
Open Access URL: https://link.springer.com/article/10.1007%2FJHEP11...
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3146238